i saw the LTT video about Egpu, and yes the performance drop it's about 30% but he didn't show if performance on real gaming are good about lag or tearing, and i have another question it will work on my notebook ? it's hard to setup ?

P.S:
i also forgot to say, i'm already using my notebook with external monitor 2560x1440

@Thedoktor84
If I remember correcly, there is guide on egpu.io for using an egpu with a p750. check this link https://egpu.io/build-guides/
A user installed a mxm gtx1060 here on NBR, check my signature for more infos

Egpu:
RazerCore X (Expansive like 300Euro) but if will not work i can turn it back (amazon)
GTX1070FE (i already have 0 euro)
External monitor (i already have it 27" 2560x1440 and 27" 1920x1080)
Need a custom bios ( hot swap PCIEXP ?)
Perfomance Boost over my gtx970m ( 2560x1440 egpu seems to drop less perfomance)
My notebook have a full thunderbolt 3 pciexp 4 lanes ?
It will be easy to install ? custom driver ? need to disable gtx970m ?
it's plug and play ? (i travel a lot) so when i go home i just want to plug the TB3 cable and play....